It is my considered opinion that casting actors according to their ethnicity is the worst part of Affirmative Action. Not casting the best actor for a role because he is not the right race is the definition of racism.

Disagree if you like, but it won't change my opinion.

Um okay, but if the character you're casting is supposed to be black or Asian or whatever, then wouldn't someone who is black or Asian or whatever be the best actor for a role?

Look, in some cases, yes, race is trivial to a character and anyone of any ethnicity can be cast. Others, race is essential. If you were doing a Martin Luther King biopic, you wouldn't cast a white guy as Martin Luther King, would you?